This invention relates to a new lead-antimonytin-arsenic alloy for use in the production of grids employed as holders of the positive electrodes in electric accumulators, preferably lead-acid accumulators.
The electric accumulators which include positive electrodes, provided as holders of the grids constituted by the new alloy in compliance with the invention, has an improved behaviour against corrosion at high temperatures.
At present, electric accumulators are required for use in motorcars with special cycling characteristics, corrosion strength and improved behaviour at high environmental temperatures. The same may be said of the batteries used for storage of power and photovoltaic applications.
As is known, lead accumulators are made up of lead dioxide anodes and sponge lead cathodes, said electrodes having been prepared as from holders or grids of equal or different alloys and with different lead sulphate compositions included into the active material. These electrodes are physically separated by a separator of a different type of material (cellulosic, plastic, glass fibre, . . . ) the purpose of which is to provide a passage of conductor ions from one electrode to another, without any physical contact with each other.
Lead alloys are described in different patents for use in batteries, with corrosion strength properties. Thus, U.S. Pat. No. 5,339,873, describes the inclusion of titanium in order to improve the corrosion strength, or of tellurium in WIPO Publication No. WO90/09462. Other European and American patents describe the use of grids of different lead alloys with the addition of silver or strontium and a low tin content (EP 0506323 A1; U.S. Pat. No. 5,298,350; U.S. Pat. No. 5,434,025; U.S. Pat. No. 4,137,378 as improved alloys for lead-acid batteries. Similarly, U.S. Pat. No. 3,078,161 mentions an alloy made up of lead-tin with silver and cobalt, free from antimony.